More information is necessary. How exactly are you trying to build it? The same source builds for me on both Debian Jessie and Ubuntu 16.10 in the openSUSE build service, and 16.10 is reasonably close to Stretch.

Anyway, whenever I've seen that type of error, it's usually due to an indent in the debian/rules file using spaces instead of a tab. If you copied code text from a browser display, it can replace tabs with spaces sometimes.

Edit: Stretch is also using gcc-6 as the default version of gcc, so you'll either have to specify that the build use the gcc-5 tools or add some magic to the build environment (usually done in the debian/rules file) like the gcc-6 fix here: https://github.com/AOSC-Dev/aosc-os-abb ... ld/prepare